After witnessing her mother’s death 3 years ago with her best friend PJ in the car, 12 year old Sam Pepper has never been able to move on. Her reclusive nature and nerd table membership leaves Sam an easy target for bullying. Trauma and puberty cause Sam and PJ to not only grow apart but become rivals.

PJ bullies Sam through ostracizing and humiliating her in front of their classmates. As Sam watches the school laugh at her through the slits of her locker, she realizes she’s had enough. Sam orders the parts to build a “Monster” from a comic book ad, and is finally able to give PJ a taste of her own medicine.

Finally, her life’s changing for the better. When her father, Roy, reveals he proposed to his girlfriend, Sydney Hart, Sam sees just how much her life’s about to change. Unable to face the state of her family, Sam relies on her monster to keep her from getting a new mom.